Circuit breaker



FIG. 1 is a perspective view the circuit breaker;

FIG. 2 is a front view the circuit breaker;

FIG. 3 is a right view the circuit breaker wherein the broken line showing of the environment is for illustrative purpose only and forms no part of the claimed design.

FIG. 4 is a left view the circuit breaker;

FIG. 5 is a bottom view the circuit breaker; and,

FIG. 6 is a top view the circuit breaker. 

The ornamental design for a “circuit breaker,” as shown and described. 